108 THE HISTORY OF CREATION. 
We perceive that Buch is here led to the fundamental 
idea of the Theory of Descent by the phenomena of the 
geography of plants, a department of biological knowledge 
which in fact furnishes a mass of proofs in favour of it. 
Darwin has minutely discussed these proofs in two separate 
chapters of his book (the 11th and 12th). Buch’s remark is 
further of interest, because it leads us to the exceedingly 
instructive comparison of the different branches of language 
with the species of organisms, a comparison which is of the 
greatest use to Comparative Philology, as well as to Compara- 
tive Botany and Zoology. Justas, for example, the different 
dialects, provincialisms, branches, and off-shoots of the 
German, Slavonic, Greco-Latin, and Irano-Indian parent lan- 
guage, are derived from a single common Indo-Germanic 
parent tongue, and just as their differences are explained by 
Adaptation, and their common fundamental characters ex- 
plained by Inheritance, so in like manner the different species, 
genera, families, orders, and classes of Vertebrate animals 
are derived from a single common vertebrate form of animal. 
Here also Adaptation is the cause of differences, Inheritance 
the cause of community of character. This interesting 
parallelism in the divergent development of the forms of 
speech and the forms of organisms has been discussed in 
the clearest’ manner by one of our first comparative philolo- 
gists, the talented Augustus Schleicher, whose premature 
death, four years ago, remains an irreparable loss, not only 
to our University of Jena, but to the whole of monistic 
science. ® 
Among other eminent German naturalists who have ex- 
pressed their belief in the Theory of Descent more or less 
distinctly, arriving at their conclusion in very various ways, 
